Double winding device for window shade without pull cord

ABSTRACT

A double winding device for a window shade includes a head rail receiving first and second cord-winding seats. First and second movable seats are movably mounted between the first and second elastic cord-winding seats and respectively include first and second pulley units. A folding/unfolding cord is wound around the first and second pulley units and has two end sections extending through a bottom wall of the head rail and extending through two sides of a shade and fixed to a bottom of the shade. The first and second elastic cord-winding seats respectively include first and second elastic cord-winding spools. A first actuation cord is wound around the first elastic cord-winding spool and has a distal end fixed to the first movable seat. A second actuation cord is wound around the second elastic cord-winding spool and has a distal end fixed to the second movable seat.

BACKGROUND OF THE INVENTION

The present invention relates to a double winding device for a window shade and, more particularly, to a double winding device that can provide a maximum folding extent in a limited space for a window shade without using a pull cord.

Window shades can provide a shield from the sun and privacy as well as decoration in rooms and can even show the taste of the users. Modern window shades generally include a pull cord to provide convenient folding/unfolding of the shade. However, the exposed length of the pull cord may strangle a child playing nearby, which problem is highlighted in countries that value human rights and demand regulations for safe window shades.

U.S. Patent Publication No. 2007/0119547 A1 (Taiwan Utility Model No. M296298) discloses a cordless window blind structure including a fixed seat and a cord-winding control unit mounted in two ends of a head rail. A movable seat is mounted in the head rail and movable between the fixed seat and the cord-winding unit. An operating cord is attached between the movable seat and the cord-winding control unit. Retrieving cords are guided through a bottom surface of the head rail. The retrieving cords are respectively led through a blind body to fix to a bottom rail at the bottommost ends. The other ends of the retrieving cords are synchronically wound around the fixed seat and the movable seat before firmly attached to the fixed seat. The bottom rail can be pushed or pulled by hands to loosen or tighten the retrieving cords and actuate the movement of the operating cord therewith to form a state of counterbalance therebetween for easy adjustment of the blind body into a desirable position.

Similarly, U.S. Pat. No. 7,398,815 B2 discloses a non-pull cord operated window blind structure including a head rail. A fixed seat and a cord-winding control unit are fixed to two ends of an accommodating channel of the head rail. A movable seat is mounted between the cord-winding control unit and the fixed seat and movable in the accommodating channel.

In the above patent and above patent publication, the retrieving cord (or collecting cord) winding extent (relative to the retrieving cord releasing extent) of the movable seat mainly depends on the spacing between the movable seat and the cord-winding control unit. The retrieving cord can be wound a plurality of rounds such that an overall displacement of the retrieving cord in the horizontal direction is equal to an overall displacement of the retrieving cord in the vertical direction. Since there is only one movable seat, longer travel and a longer period of time are required during folding/unfolding operation. Furthermore, the retrieving cord having a considerable horizontal displacement must be wound around the fixed seat and the movable seat more rounds such that the force gradually lessens, failing to provide effective transmission of force to the blind body. Due to the lack of sufficient tension, an intermediate section between two ends of one or more of the retrieving cords is liable to entangle and may cause the bottom rail and the blind body to be in a slanted state. Furthermore, it is difficult to obtain large-extent folding/unfolding of the blind body by short, horizontal displacement of the retrieving cord without increasing the horizontal travel of movable seat.

BRIEF SUMMARY OF THE INVENTION

In a first aspect of the present invention, a double winding device is provided for a window shade without a pull cord. The double winding device includes a head rail having a compartment with a bottom wall. First and second cord holes are formed in the bottom wall of the compartment. First and second movable seats are movably mounted in the compartment. The first movable seat includes a first pulley unit, and the second movable seat includes a second pulley unit. A folding/unfolding cord is wound around the first and second pulley units. The folding/unfolding cord has two end sections respectively extending through the first and second cord holes and are adapted to be extended through two sides of a shade and fixed to a bottom of the shade. First and second elastic cord-winding seats are mounted in the compartment. The first movable seat is located between the first elastic cord-winding seat and the second movable seat. The second movable seat is located between the second elastic cord-winding seat and the first movable seat. The first and second elastic cord-winding seats respectively include a first elastic cord-winding spool and a second elastic cord-winding spool. A first actuation cord is wound around the first elastic cord-winding spool and has a distal end fixed to the first movable seat. A second actuation cord is wound around the second elastic cord-winding spool and has a distal end fixed to the second movable seat.

In a second aspect of the present invention, a double winding device includes a head rail having a compartment with a bottom wall. First and second cord holes are formed in the bottom wall of the compartment. First and second movable seats are movably mounted in the compartment. The first movable seat includes a first pulley unit, and the second movable seat includes a second pulley unit. A folding/unfolding cord is wound around the first and second pulley units. The folding/unfolding cord has two end sections respectively extending through the first and second cord holes and are adapted to be extended through two sides of a shade and fixed to a bottom of the shade. An elastic cord-winding seat is mounted in the compartment. The first movable seat is located between the first elastic cord-winding seat and the second movable seat. The first elastic cord-winding seat includes a first elastic cord-winding spool and a second elastic cord-winding spool. A first actuation cord is wound around the first elastic cord-winding spool and has a distal end fixed to the first movable seat. A second actuation cord is wound around the second elastic cord-winding spool and has a distal end fixed to the second movable seat.

The double winding device according to the preferred teachings of the present invention uses two movable seats by replacing the fixed seat in the conventional designs with a movable seat, which is not a simple increase or reduction of the number of components. Specifically, by using two movable seats, the horizontal displacement can be achieved by shorter travel and in a shorter period of time. Another advantage of using two movable seats is that the folding/unfolding cord is provided with sufficient tension to reduce the possibility of entanglement, reliably positioning the shade in a horizontal state during folding/unfolding operation. A further advantage of using two movable seats is that the output force will not lessen too much even if the folding/unfolding cord are wound many rounds. This is because the output force acts on two points. Thus, the folding/unfolding cord can be wound more rounds such that a large-extent folding/unfolding of the shade can be achieved through short, horizontal displacement of the movable seats.

The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

The illustrative embodiments may best be described by reference to the accompanying drawings where:

FIG. 1 shows a perspective view of a double winding device for a window shade without a pull cord of an embodiment according to the present invention.

FIG. 2 shows an exploded, perspective view of the double winding device of FIG. 1.

FIG. 3 shows a top view of the double winding device of FIG. 1 with the double winding device in an initial state.

FIG. 4 shows a front view of the double winding device of FIG. 3 with a shade attached to the double winding device and in a folded state.

FIG. 5 shows a top view of the double winding device of FIG. 1 with first and second movable seats of the double winding device moved toward each other.

FIG. 6 shows a front view of the double winding device and the shade of FIG. 4 with the first and second movable seats moved toward each other and with the shade in an unfolded state.

FIG. 7 shows a perspective view of a double winding device of another embodiment according to the present invention.

FIG. 8 shows an exploded, perspective view of the double winding device of FIG. 7.

FIG. 9 shows a top view of a double winding device of FIG. 1 using two folding/unfolding cords.

FIG. 10 shows a side view of the double winding device of FIG. 9 with two shades attached to the double winding device.

FIG. 11 shows an exploded, perspective view of a pulley unit according to the preferred teachings of the present invention.

All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiments will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1-6, a double winding device for a window shade without a pull cord of an embodiment according to the present invention includes a head rail 1 having a compartment 10. Two cord holes 11 and 12 are formed in a bottom wall of the compartment 10. It can be appreciated that the bottom wall of the compartment 10 can include more than two cord holes. Two end caps 13 and 14 are mounted to two ends of the head rail 10 to seal two ends of the compartment 10.

The double winding device further includes first and second movable seats 2 and 3 mounted in the compartment 10. The first movable seat 2 includes a first pulley unit 21. The second movable seat 3 includes a second pulley unit 31. A first folding/unfolding cord 23 is wound around the first and second pulley units 21 and 31. Two end sections 23A and 23B of the first folding/unfolding cord 23 are respectively extended through the cord holes 11 and 12 and can be extended through two sides of a shade 5 and fixed to two points P1 of a bottom of the shade 5.

The first movable seat 2 and the second movable seat 3 are substantially identical. The first movable seat 2 includes a body 20 receiving the first pulley unit 21. The head rail 1 includes two opposite vertical walls 16, and a ledge 15 is formed on each vertical wall 16 (FIG. 2). With reference to FIG. 11, at least one first wheel 202 is rotatably mounted to each of two lateral sides of the body 20 and rollable along one of the ledges 15 of the head rail 1. At least one second wheel 203 is rotatably mounted to each lateral side of the body 20 and rollable along one of the vertical walls 16. In the example shown in FIG. 11, two first wheels 202 and two second wheels 203 are rotatably mounted to each lateral side of the body 20. Thus, the first and second movable seats 2 and 3 can stably move in the head rail 1.

The first pulley unit 21 and the second pulley unit 31 are substantially identical. With reference to FIG. 11, the first pulley unit 21 includes at least one roller 211. The number of the rollers 211 can be selected according to the desired rounds of folding/unfolding cord 23. In the example shown in FIG. 11, the first pulley unit 21 includes three rollers 211. When two or more rollers 211 are used, an axle 210 can be extended through the rollers 211 such that rollers 211 can rotate independently about the axle 210, increasing rotating efficiency and avoiding mutual interference and impedance. The body 20 includes at least one partitioning board 201. In the example shown in FIG. 11, the body 20 includes two partitioning boards 201 each having a slot 201A. The axle 210 is extended through the slots 201A, and the rollers 211 are spaced by the partitioning boards 201.

A first elastic cord-winding seat 4 is mounted in the compartment 10 and adjacent to one of the first and second movable seats 2 and 3. In the embodiment shown in FIGS. 1-6, the first movable seat 2 is between the first elastic cord-winding seat 4 and the second movable seat 3. The first elastic cord-winding seat 4 includes a first elastic cord-winding spool 41 and a second elastic cord-winding spool 42. Each of the first and second elastic cord-winding spools 41 and 42 includes an elastic member such as a spiral spring for winding a folding/unfolding cord. The spiral springs for winding folding/unfolding cords are conventional and, thus, not described in detail to avoid redundancy. A first actuation cord 411 is wound around the first elastic cord-winding spool 41, and a second actuation cord 421 is wound around the second elastic cord-winding spool 42. A distal end of the first actuation cord 411 is fixed to the first movable seat 2. A distal end of the second actuation cord 421 is fixed to the second movable seat 3.

With reference to FIGS. 3 and 4, in an initial state of the double winding device according to the present invention, the shade 5 is in a folded state such that it is not necessary to release the end sections 23A and 23B, and the first and second movable seats 2 and 3 have a larger spacing therebetween.

With reference to FIGS. 5 and 6, when a user moves the shade 5 downward and, thus, releases the end sections 23A and 23B, the first and second movable seats 2 and 3 move toward each other and, thus, have a smaller spacing therebetween. Since there are two movable seats 2 and 3, the horizontal displacement can be shared by the two movable seats 2 and 3. The end sections 23A and 23B can be released to a larger extent through relatively small horizontal displacement of the first folding/unfolding cord 23. The horizontal displacement of the first folding/unfolding cord 23 can be further decreased if the first folding/unfolding cord 23 is wound more rounds between the first and second movable seats 2 and 3.

Thus, the horizontal displacement of the first folding/unfolding cord 23 can be achieved by shorter travel and in a shorter period of time. Furthermore, the spacing between the first and second movable seats 2 and 3 permits sufficient tension imparted to the first folding/unfolding cord 23, reducing the possibility of entanglement of the first folding/unfolding cord 23 and reliably positioning the shade 5 in a horizontal state during folding/unfolding operation.

Furthermore, the moving distance between the first and second movable seats 2 and 3 is shortened. The output force will not lessen too much even if the folding/unfolding cord 23 is wound many rounds. This is because the output force acts on two points. Thus, the retrieving cords can be wound more rounds such that a large-extent folding/unfolding of the shade 5 can be achieved through short, horizontal displacement of the movable seats 2 and 3.

In another embodiment shown in FIGS. 7 and 8, a second elastic cord-winding seat 6 is mounted in the compartment 10 and adjacent to second movable seat 3. In this embodiment, the first movable seat 2 is between the first elastic cord-winding seat 4 and the second movable seat 3, and the second movable seat 3 is between the second elastic cord-winding seat 6 and the first movable seat 2. Namely, the first and second movable seats 2 and 3 are located between the first and second elastic cord-winding seats 4 and 6. The first and second elastic cord-winding seats 4 and 6 respectively include a first elastic cord-winding spool 41 and a second elastic cord-winding spool 61. Each of the first and second elastic cord-winding spools 41 and 61 includes an elastic member such as a spiral spring for winding a folding/unfolding cord. The spiral springs for winding folding/unfolding cords are conventional and, thus, not described in detail to avoid redundancy. A first actuation cord 411 is wound around the first elastic cord-winding spool 41, and a second actuation cord 611 is wound around the second elastic cord-winding spool 61. A distal end of the first actuation cord 411 is fixed to the first movable seat 2. A distal end of the second actuation cord 611 is fixed to the second movable seat 3.

With reference to FIGS. 9 and 10, a second folding/unfolding cord 22 can be wound around the first and second pulley units 21 and 31. Two end sections 22A and 22B of the second folding/unfolding cord 22 can be respectively extended through two additional cord holes 11 and 12 of the bottom wall of the head rail 13 and can be extended through two sides of another shade 7 and fixed to two points P1 of a bottom of the shade 7. The shade 5 is in front of or behind the shade 7. The user can operate the shades 5 and 7 separately or at the same time. The shades 5 and 7 can be made of different materials. As an example, one of the shades 5 and 7 can be heavy and thick to provide a shielding effect, and the other can be light and thin to allow transmission of light beams. The shades 5 and 7 can be used together or independently.

Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. 

1. A double winding device for a window shade without a pull cord, with the double winding device comprising: a head rail including a compartment having a bottom wall, with first and second cord holes formed in the bottom wall of the compartment; first and second movable seats movably mounted in the compartment, with the first movable seat including a first pulley unit, with the second movable seat including a second pulley unit, with a folding/unfolding cord wound around the first and second pulley units, with the folding/unfolding cord having two end sections respectively extending through the first and second cord holes and adapted to be extended through two sides of a shade and fixed to a bottom of the shade; and first and second elastic cord-winding seats mounted in the compartment, with the first movable seat located between the first elastic cord-winding seat and the second movable seat, with the second movable seat located between the second elastic cord-winding seat and the first movable seat, with the first and second elastic cord-winding seats respectively including a first elastic cord-winding spool and a second elastic cord-winding spool, with a first actuation cord wound around the first elastic cord-winding spool and having a distal end fixed to the first movable seat, with a second actuation cord wound around the second elastic cord-winding spool and having a distal end fixed to the second movable seat.
 2. The double winding device as claimed in claim 1, with the first pulley unit including at least one roller.
 3. The double winding device as claimed in claim 2, with said at least one roller of the first pulley unit including three rollers.
 4. The double winding device as claimed in claim 3, with the first pulley unit further including an axle extending through the three rollers, with the three rollers being independently rotatable about the axle.
 5. The double winding device as claimed in claim 1, with the first movable seat including a body, with the body receiving the first pulley unit, with the head rail including two opposite vertical walls, with a ledge formed on each of the two vertical walls, with at least one first wheel rotatably mounted to each of two lateral sides of the body and rollable along one of the ledges of the head rail, with at least one second wheel rotatably mounted to each of the two lateral sides of the body and rollable along one of the two vertical walls.
 6. A double winding device for a window shade without a pull cord, with the double winding device comprising: a head rail including a compartment having a bottom wall, with first and second cord holes formed in the bottom wall of the compartment; first and second movable seats movably mounted in the compartment, with the first movable seat including a first pulley unit, with the second movable seat including a second pulley unit, with a folding/unfolding cord wound around the first and second pulley units, with the folding/unfolding cord having two end sections respectively extending through the first and second cord holes and adapted to be extended through two sides of a shade and fixed to a bottom of the shade; and an elastic cord-winding seat mounted in the compartment, with the first movable seat located between the first elastic cord-winding seat and the second movable seat, with the first elastic cord-winding seat including a first elastic cord-winding spool and a second elastic cord-winding spool, with a first actuation cord wound around the first elastic cord-winding spool and having a distal end fixed to the first movable seat, with a second actuation cord wound around the second elastic cord-winding spool and having a distal end fixed to the second movable seat.
 7. The double winding device as claimed in claim 6, with the first pulley unit including at least one roller.
 8. The double winding device as claimed in claim 7, with said at least one roller of the first pulley unit including three rollers.
 9. The double winding device as claimed in claim 8, with the first pulley unit further including an axle extending through the three rollers, with the three rollers being r independently rotatable about the axle.
 10. The double winding device as claimed in claim 6, with the first movable seat including a body, with the body receiving the first pulley unit, with the head rail including two opposite vertical walls, with a ledge formed on each of the two vertical walls, with at least one first wheel rotatably mounted to each of two lateral sides of the body and rollable along one of the ledges of the head rail, with at least one second wheel rotatably mounted to each of the two lateral sides of the body and rollable along one of the two vertical walls. 